The present invention relates to an optical waveguide device, and more particularly to an optical waveguide device using a semiconductor laser beam as an incident light.
In a conventional optical waveguide device having an optical waveguide in an optical modulator, SHG (second harmonic generator), optical integrated circuit, etc., a semiconductor laser is used as an incident light source for the optical waveguide.
It is desired that the semiconductor laser and the optical waveguide are to be optically coupled together with the utmost coupling efficiency. It is therefore necessary to effect accurate alignment between a light exit end of the semiconductor laser and a light entry end of the optical waveguide.
There have conventionally been proposed various coupling methods considering such accurate alignment. In Japanese Patent Laid-open Publication No. 57-118686, for example, there is disclosed a structure that a semiconductor laser and an optical waveguide substrate are mounted on a common silicon substrate. In this structure, the alignment (equalization in level) between a light exit end of the semiconductor laser and a light entry end of the optical waveguide is effected by forming a recess on the silicon substrate and locating the semiconductor laser in this recess.
However, this prior art method has a problem in working such that a high accuracy is required in working the silicon substrate, for example.